Velocity, Acceleration, Car problem

[M1ZeN]

Homework Statement

A car accelerates at 2.0 m/s^2 along a straight road. It passes two marks that are 30 m apart at times t = 4.0s and t = 5.0s. What was the car's velocity at t = 0s?

Homework Equations

There are some equations in the chapter that I have used for previous homework problems but for this one I'm not sure which one or ones to use.

(Vf)^2 = (Vi)^2 + 2ad
(d = distance)
a = vf - vi/t
d = vt + 1/2a(t)^2

The Attempt at a Solution

I have tried finding the initial velocity at t = 0s but I can't seem to find a way to utilize the other variables.

Thanks.

Daniel

 

[rl.bhat]

Using the first equation, find vf^2 - vi^2.
Using second equation find vf - vi.
From these two equations, find vf + vi.
Solve the above two equations to get vi and vf.
Here vi is the velocity a the end of 4 second, From that you can find v0 at t = 0